ECS Types

The cloud platform provides the following ECS types for different application scenarios:

General computing
Dedicated general-purpose
Memory-optimized
Disk-intensive
GPU-accelerated

ECS Flavor Naming Rules

ECS flavors are named in the "AB.C.D" format.

Example: s6.medium.4

The format is defined as follows:

A specifies the ECS type. For example, s indicates a general-purpose ECS, c a general computing-plus ECS, and m a memory-optimized ECS.
B specifies the type ID. For example, 6 in s6 indicates the six-generation general-purpose ECS.
C specifies the flavor size, such as medium, large, xlarge, 2xlarge, 4xlarge, or 8xlarge.
D specifies the ratio of memory to vCPUs expressed in a digit. For example, value 4 indicates that the ratio of memory to vCPUs is 4.

vCPU

The processor uses the hyper-threading technology. The CPU exposes two execution contexts per physical core. This means that one physical core now works like two "logical cores" that can handle different software threads.

For example, a 10-core physical CPU contains 20 vCPUs (threads).

Network QoS

Network QoS uses basic technologies to improve the quality of network communication. A network with QoS enabled offers predictable network performance and effectively allocates network bandwidth to use network resources.

The intranet bandwidth and PPS of an ECS are determined by the ECS flavor.

Assured intranet bandwidth: indicates the guaranteed bandwidth allocated to an ECS when there is a network bandwidth contention in the entire network.
Maximum intranet bandwidth: indicates the maximum bandwidth that can be allocated to an ECS when the ECS does not compete for network bandwidth (other ECSs on the host do not have high requirements on network bandwidth).
Maximum intranet PPS: indicates the maximum ECS capability in sending and receiving packets.
PPS: packets per second, indicates the number of packets sent per second. It is usually used to measure the network performance.
NIC multi-queues: allocates NIC interrupt requests to multiple vCPUs for higher PPS performance and bandwidth
Maximum NICs: indicates the maximum number of NICs that can be attached to an ECS.
- For instructions about how to test packet transmit and receive, see How Can I Test Network Performance?
- For instructions about how to enable NIC multi-queue, see Enabling NIC Multi-Queue.
- The maximum bandwidth is the total bandwidth allocated to an ECS. If an ECS has multiple NICs, the sum of the maximum bandwidths allocated to all NICs cannot exceed the maximum bandwidth allocated to the ECS.

Dedicated and Shared ECSs

**Table 1** Differences between dedicated and shared ECSs
Dimension	Dedicated ECS	Shared ECS
CPU Allocation	CPUs are exclusively used and there is no CPU contention.	CPUs are shared and CPU contention may occur.
Feature	High performance Dedicated and stable computing, storage, and network resources High costs	Unstable performance when loads are high Shared computing, storage, and network resources Low costs
Application Scenario	For enterprises that have high requirements on service stability	For small- and medium-sized websites or individuals that have requirements on cost-effectiveness
ECS Specifications	Specifications except general computing	x86 computing: General computing